Systems and methods for synthesizing GPS measurements to improve GPS location availability
First Claim
1. A method for synthesizing global navigation satellite system (GNSS) measurements, the method comprising:
- receiving, by a navigation device, a GNSS signal from a signal source;
calculating pseudoranges (PRs) and delta pseudo ranges (DPRs) associated with the GNSS signal;
identifying the signal source as a lost signal source when the GNSS signal is not being received;
estimating PRs and DPRs for the lost signal source based on previously calculated PRs and DPRs of the lost signal source;
determining a position of the navigation device using dead reckoning;
determining a validity of the estimated PRs and DPRs based on the dead reckoning; and
calculating a position fix using the calculated PRs and DPRs, and the estimated PRs and DPRs in a navigation solution based on the determined validity of the estimated PRs and DPRs.
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Accused Products
Abstract
There are situations where GPS signals are received from less than four satellites. In order to improve the GPS location availability, disclosed here are systems and methods for synthesizing GPS measurements, which, together with fewer than four available real GPS signals, can be used to calculate a position fix. In particular, GPS range measurements for lost satellites, which are satellites that were previously tracked but are now not tracked, are synthesized to improve GPS signal availability. The synthesized measurements are used along with real measurements to enable accurate position fix even when GPS satellite availability is poor. Different synthesized measurement generation schemes, depending on whether an INS/DR aiding system is available, are further described herein.
22 Citations
20 Claims
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1. A method for synthesizing global navigation satellite system (GNSS) measurements, the method comprising:
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receiving, by a navigation device, a GNSS signal from a signal source; calculating pseudoranges (PRs) and delta pseudo ranges (DPRs) associated with the GNSS signal; identifying the signal source as a lost signal source when the GNSS signal is not being received; estimating PRs and DPRs for the lost signal source based on previously calculated PRs and DPRs of the lost signal source; determining a position of the navigation device using dead reckoning; determining a validity of the estimated PRs and DPRs based on the dead reckoning; and calculating a position fix using the calculated PRs and DPRs, and the estimated PRs and DPRs in a navigation solution based on the determined validity of the estimated PRs and DPRs. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A global navigation satellite system (GNSS) receiver comprising:
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an antenna configured to receive a GNSS signal from a signal source; and a baseband processor configured to; calculate pseudoranges (PRs) and delta pseudo ranges (DPRs) associated with the GNSS signal, identify the signal source as a lost signal source when the GNSS signal is not being received, estimate PRs and DPRs for the lost signal source based on previously calculated PRs and DPRs of the lost signal source, determine a position of the navigation device using dead reckoning, determine a validity of the estimated PRs and DPRs based on the dead reckoning, and calculate a position fix using the calculated PRs and DPRs, and the estimated PRs and DPRs in a navigation solution based on the determined validity of the estimated PRs and DPRs. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system for synthesizing global navigation satellite system (GNSS) measurements comprising:
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a GNSS receiver configured to; receive a GNSS signal, calculate pseudoranges (PRs) and delta pseudo ranges (DPRs) associated with the GNSS signal, identify the signal source as a lost signal source when the GNSS signal is not being received, estimate PRs and DPRs for the lost signal source based on previously calculated PRs and DPRs of the lost signal source, determine a position of the GNSS receiver using dead reckoning; and an aiding server configured to; receive the PRs and DPRs and the estimated PRs and DPRs from the GNSS receiver, determine a validity of the estimated PRs and DPRs based on the dead reckoning, calculate a position fix using the calculated PRs and DPRs, and the estimated PRs and DPRs in a navigation solution based on the determined validity of the estimated PRs and DPRs, and transmit the position fix to the GNSS receiver. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification